In this study, comparative evaluation of fluorescent carbon nanodots (C-Dots) prepared using carob molasses was reported by screening various biocompatible macromolecules as passivating agent (PA). Incorporation of PAs with different molecular weight, polarity, and chemical structure was examined, and compared with the polyethylene glycol (PEG, Mn = 10 kN) passivated and pristine C-Dots. Not only the fluorescence properties but also many other features including size, crystal structure, colloidal conductivity, resistance to photobleaching, quantum yield, and UV-modulated surface interaction of them with the reactive oxygen species (ROS) as well as ROS production were investigated. Photoluminescence (PL) capacity of C-Dots was found to be associated with the number of surface alkyl groups and polymeric hydrogen bonding present on the C-Dot surface (increased number is associated with decreased PL) while the surface conductivity of C-Dots in water was proportional to the PL intensity. More importantly, C-Dots with relatively poorer fluorescent were investigated in various organic solvents (hexane, methanol, acetone, ethanol, dimethylformamide (DMF), and DMSO). As happens with the fluorescent dyes, their PL intensities were significantly enhanced (even for pristine C-Dots) depending on the solvent characteristics. All of the C-Dots synthesized were further evaluated by means of UV-induced generation of ROS and inhibition of ROS by using H2O2 as a model. In contrary to other carbonaceous nanomaterials, they did not show any ROS generation, on the contrary, they showed ROS scavenging activity that can be modulated by UV-irradiation (λexc = 365 nm). PEG and alginate passivated C-Dots inhibited H2O2 activity at LC50 values below 10 mg/mL.

In this research article , synthesis of fluorescent carbon nanoparticles from a natural carbon source, carob molasses, was investigated. To this end, thermal synthesis methodology as a green synthesis method with the easiness to carry out and being economical was followed and polyethylene glycol of different molecular weight (PEG Mn: 300~20000) was used as surface passivating agent. Synthesized fluorescent carbon nanoparticles (FCNPs) were then characterized by field emission scanning electron microscope (FE-SEM), transmission electron microsocope (TEM), X-Ray Diffraction Analysis (XRD), UV spectrophotometer, fluorescence spectrophotometer, dynamic light scattering (DLS) methods. Results showed that surface properties of nanoparticles and fluorescent properties as a result were found to be determined by the molecular weight of the passivation agent. Moreover, hydrodynamic size of nanoparticles with core diameter measured as 10-15 nm was also found to be increased with increased polymer Mn.

In this study, hierarchical self-assembly of photocatalytic nanodisks through non-covalent interactions between spinach-extracted chlorophyll molecules and trimethylammonium hydroxide-coated magnetic iron oxide nanoparticles was discussed. Combination of chlorophyll molecules with iron oxide nanoparticles generated an alteration in light absorption at both visible and near-IR region with accompanying enhancement in fluorescence emission. Further, photocatalytic role of resulting molecular assembly was studied by means of the photoinduced degradation of methylene blue dye under UV light and direct sun irradiation at neutral pH. In order to enhance the long-term stability of the hybrid nanocatalyst, commercially available cellulose membrane was used as a support and magnetic recovery and reusability was achieved where the nanocatalyst retained more than 90 % of its efficiency even after four cycles. This simple strategy could initiate the development of new materials for wastewater treatment including membrane-based technologies. On the other hand, their sunlight-induced photocatalytic activity could easily be conducted to dye-synthesized solar cells or their enhanced photoluminescence can provide a strong basis for future bioimaging tools.

In this study, magnetic alginate beads were successfully synthesized by integrating superparamagnetic iron oxide nanoparticles (Fe3O4) in sodium alginate microbeads during the synthesis. The as-obtained dried samples were analyzed by means of their water detention capacity and drug encapsulation efficiency. Further, an anti-inflammatory drug (Cefazolin), mostly used for the treatment of joint inflammations after surgery, was used as a model drug in order to evaluate the stimuli-responsive properties of macrocomposites under magnetic field for the development of on-site drug delivery system. To do so, their drug release kinetics at changing environmental conditions, such as pH, temperature, and magnetic field were investigated and compared with bare alginate beads.

Our undergrad student Zeynep Meray was awarded to TUBITAK 2209-A – Research Projects Support Program for Undergraduate Students with her graduate project entitled in “Photosystem I-magnetic nanoparticle composites for solar cell applications: Synthesis and Characterization”. We congratulate her for the efforts and wish her a successful academic life.

Lumps of gold moulded into rings, coins and ingots have been highly prized for millennia. But recently, scientists have realized that nanoparticles of the metal could also become a valued commodity. In labs around the world, gold nanoparticles are being tested as components in technology and medicines. See how gold could be used to kill cancer cells, improve the efficiency of solar cells and catalyse chemical reactions.

Novelchip made a heart like micro-pump. It works as a pump which can pump some milliliters per minute and visually fakes the “heart beat”. Check the video below and have fun with this interesting micro-fluidic chip design.

(Phys.org) —A combined team of researchers from Spain and Australia has discovered what they claim is the first known instance of a biomaterial that can kill bacteria on contact based only its physical surface structure. In their paper published in Biophysical Journal, the team describes how they found that clanger cicadas have nanoscale sized pillars on their wings that trap and slowly kill bacteria by pulling their cells apart.